A known entrapment prevention sensor will be explained with reference to FIGS. 1 to 3. An opening and closing door 2 of a vehicle, which is of a power-driven opening and closing type and is hinged at the top of a body 4, is equipped with an entrapment prevention sensor 40 that detects securely an entrapment of an obstacle such as a hand of a passenger between the opening and closing door 2 and the body 4. The entrapment prevention sensor 40 generally includes a sensor main body 41 that detects an obstacle, and a protector 42 incorporating the sensor main body 41. The protector 42 includes a hollow portion 42a and a fitting portion 42b having a U shape in cross section. The fitting portion 42b is assembled onto a fitting flange 3 provided at the opening and closing door 2 while the hollow portion 42a accommodates the sensor main body 41. Alternatively, as disclosed in JP2004-176426A, the protector is integrally formed by means of both extrusion molding and die molding.
Because the protector 42 cannot be formed into a curved shape, the aforementioned entrapment prevention sensor 40 cannot be applied at a corner portion C. Thus, in the opening and closing door 2 of which a lower half portion is formed narrower than an upper half portion as illustrated in FIG. 1, for example, a first sensor portion 40a and a second sensor portion 40b that are individually and separately constituted are both required on right side and left side of the opening and closing door 2.
Accordingly, a non-detectable area N is present between the first sensor portion 40a and the second sensor portion 40b where the sensor main body 41 is not provided. The entrapment of an obstacle such as a hand cannot be detected in the non-detectable area N, which raises an issue that the entrapment cannot be avoided. Further, since the first sensor portion 40a and the second sensor portion 40b are constituted by two separate members, a manufacturing cost may increase and a fitting process may be troublesome.
In the cases where the corner portion is integrally formed by means of extrusion molding and die molding such as illustrated in FIG. 4 of JP2004-176426A, the molding method is complicated and thus a cost increase may be inevitable. As described in a paragraph [0031] of JP2004-176426A, a pressure detection sensor is inserted through a sensor insertion slit formed at a corner door seal portion, which may require a difficult process. According to other examples illustrated in FIGS. 6 and 7 of JP2004-176426A, a fitting portion of a weather strip is arranged without cutting at the corner portion. As a result, a portion of the fitting portion that is in contact with an end portion of a flange and a most outer circumferential portion of a sensor receiving portion differ in view of a circumferential length. The sensor receiving portion having a round hollow shape in cross section is squashed and deformed towards the fitting portion to thereby form into an ellipse shape. Accordingly, the pressure detection sensor is constantly squashed and deformed, which may cause a wrong operation because of hypersensitive reaction.
Thus, a need exists for an entrapment prevention sensor provided between an opening and closing door of a vehicle and a periphery of a body opening portion that can be arranged at a corner portion of the door so as to securely detect an entrapment without a wrong operation and that can achieve a low manufacturing cost and a simple assembly operation.